1. Field of the Invention
This invention relates to spun yarn comprising polyester staple fiber and cotton, more particularly such a yarn in which the polyester staple is a bicomponent that imparts desirable properties to the yarn, and to polyester bicomponent staple fibers having selected properties, more particularly such fibers comprising poly(ethylene terephthalate) and poly(trimethylene terephthalate).
2. Discussion of Background Art
Polyester bicomponent fibers are known from U.S. Pat. Nos. 3,454,460 and 3,671,379, which disclose spun yarns made from bicomponent staple having certain ranges of crimp properties outside of which the yarns are said to be boardy, harsh, and aesthetically undesirable.
Spun yarns comprising bicomponent staple fibers are also disclosed in Japanese Published Patent Applications JP62-085026, and JP2000-328382 and in U.S. Pat. Nos. 5,723,215 and 5,874,372, but such fibers can have little recovery power and can require mechanical crimping which adds to their cost.
Polyester fibers having longitudinal grooves in their surfaces are described in U.S. Pat. Nos. 3,914,488, 4,634,625, 5,626,961, and 5,736,243, and Published International Patent Application WO01/66837, but such fibers typically lack good stretch and recovery properties.
Published International Application WO00-77283 discloses tows of polyester bicomponent fibers, but such tows are said to require ‘de-registering’ to be useful, an added cost.
Spun yarns of polyester bicomponent staple fibers and cotton that have high stretch and uniformity characteristics are still needed, as are polyester bicomponent staple fibers having both improved processability and stretch and recovery properties.